Oh hey, I'm an auditory scientist who studies hearing loss, hearing aids, and self-fitting and other "alternative-fit" audio devices. I'm going to copy a bit from my latest paper that touches on this (TL;DR at the bottom).
"A central problem of hearing aid fitting is that the space of gain-frequency responses that can be achieved with digital hearing aids is extremely large, but only a subset of those responses could reasonably be audiologically appropriate for any particular ear. Client-based selection of amplification has historically involved some combination of restricting the number of individual gain-frequency responses available (e.g., Humes et al., 2017) and providing efficient methods for navigating the space of gain-frequency responses (e.g., Sabin et al., 2020). The approach of offering a choice between three presets was found to be efficacious in clinical trials of a client-driven delivery model (Humes et al., 2017, 2019). Recent work suggests that as few as four gain-frequency responses can provide audiologically appropriate fits to 60%–75% of adults with mild-to-moderate sensorineural loss (Jensen et al., 2020; Urbanski et al., 2021). Greater coverage can be achieved by expanding the number of gain-frequency responses available to the wearer (Sabin et al., 2021). In a field trial of a self-adjustment tool that provided clients with a large range of gain-frequency responses, participants showed slight preferences for self-adjusted settings over clinician-fit settings, and no group-level differences in clinical measures of amplification benefit were observed (Sabin et al., 2020)."
Perry, T. T., & Nelson, P. B. (2022). Self-Adjustment of Hearing Aid Amplification for Lower Speech Levels: Independent Ratings, Paired Comparisons, and Speech Recognition. American Journal of Audiology, 1-17.
TL;DR: Some products will come with 4 or 5 presets that you can choose between and then tweak slightly. Some products will come with software (such as a smartphone app) that includes simplified (yet effective!) user interfaces for the wearer to self-adjust the amplification. Some products will ask you to engage in a computerized hearing test to set the device to levels prescribed by an audiogram-based fitting prescription formula. We will see many more audiologists and hearing instrument specialists modifying their service delivery models to invite people to bring their already-purchased OTC hearing aids in and have them programmed by a specialist.
You have probably considered this, but just to wonder about an option, might a larger (say 15 or 30 total) preset space be searched by a user, UX-wise, via A/B testing or better/worse responses?
Yes, in fact, there have been scientists investigating the most efficacious algorithms for self-selection of hearing aid amplification since the mid '80s that continues up to today. The modern versions of it are self-adjustment tools like EarMachine ( https://apps.apple.com/us/app/earmachine/id732177210 ) which is the tool I used in my research, or what's called "trainable hearing aids" which have algorithms that observe how you adjust the hearing aid in day-to-day life in different acoustic environments and then try to predict and apply your preferred settings based on the acoustic environment ( https://www.tandfonline.com/doi/full/10.1080/14992027.2016.1... ). These different types of technologies can be (and often are) used together.
"A central problem of hearing aid fitting is that the space of gain-frequency responses that can be achieved with digital hearing aids is extremely large, but only a subset of those responses could reasonably be audiologically appropriate for any particular ear. Client-based selection of amplification has historically involved some combination of restricting the number of individual gain-frequency responses available (e.g., Humes et al., 2017) and providing efficient methods for navigating the space of gain-frequency responses (e.g., Sabin et al., 2020). The approach of offering a choice between three presets was found to be efficacious in clinical trials of a client-driven delivery model (Humes et al., 2017, 2019). Recent work suggests that as few as four gain-frequency responses can provide audiologically appropriate fits to 60%–75% of adults with mild-to-moderate sensorineural loss (Jensen et al., 2020; Urbanski et al., 2021). Greater coverage can be achieved by expanding the number of gain-frequency responses available to the wearer (Sabin et al., 2021). In a field trial of a self-adjustment tool that provided clients with a large range of gain-frequency responses, participants showed slight preferences for self-adjusted settings over clinician-fit settings, and no group-level differences in clinical measures of amplification benefit were observed (Sabin et al., 2020)."
Perry, T. T., & Nelson, P. B. (2022). Self-Adjustment of Hearing Aid Amplification for Lower Speech Levels: Independent Ratings, Paired Comparisons, and Speech Recognition. American Journal of Audiology, 1-17.
TL;DR: Some products will come with 4 or 5 presets that you can choose between and then tweak slightly. Some products will come with software (such as a smartphone app) that includes simplified (yet effective!) user interfaces for the wearer to self-adjust the amplification. Some products will ask you to engage in a computerized hearing test to set the device to levels prescribed by an audiogram-based fitting prescription formula. We will see many more audiologists and hearing instrument specialists modifying their service delivery models to invite people to bring their already-purchased OTC hearing aids in and have them programmed by a specialist.